Advanced FEM for Strongly Coupled Fluid-Structure Interactions in Offshore Applications Including Low and Zero Mass Ratios

用于海上应用（包括低质量比和零质量比）强耦合流固耦合的先进有限元法

• 批准号: RGPIN-2014-06314
• 负责人: Etienne, Stéphane
• 金额: $ 1.75万
• 依托单位: École Polytechnique de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=612156
• 关键词: Advanced; FEM; Strongly; Coupled; Fluid

Fluid-Structure Interactions (FSI) are critical to the design of many engineering systems. From sea-worthiness to airplane maneuverability, nearly all mechanical systems involve a certain degree of coupling between structures and fluid flows. At the Ecole Polytechnique de Montréal, we have developed effective monolithic fully coupled algorithms for generic FSI with flexible structures for 3D unsteady configurations. Our work has generated sufficient interest that several companies have funded extensions of our research (Gaz Transport & Technigaz, Commissariat à l’Énergie Atomique, TOTAL SA). The research we propose is a natural extension of our previous research on simulation of FSI. It will focus on fundamental formulation and computational issues (contact, spectral element method) for accurate and consistent finite element simulation of structures undergoing large displacements and deformations induced by the flow of incompressible fluids. Our goal is to extend FSI formulations to tackle outstanding while typical challenges in the offshore industry: flow induced vibrations of offshore structures with very low (zero) mass ratios, in-line with the flow arrangements of risers and galloping of riser towers. The usual decoupled algorithms fail miserably on these problems. Also, the current trend to drill in ever deeper waters implies that riser lines carrying the oil from the ocean floor to the surface now span more than 2000 m which requires that new buoyancy devices and new riser concepts be designed. Risers, buoys and riser towers dynamical behaviors result from strong Flow Induced Vibrations that are poorly handled by traditional loosely coupled algorithms. We believe that our fully coupled approach can overcome many of the difficulties presented by these new extreme FSI. To achieve our goal we have identified the following objectives: 1. REFINE our fully coupled monolithic computational method to improve its accuracy and computational efficiency. We will extend our FE Formulation to isoparametric, higher order spectral elements to improve spatial accuracy and benefit from their higher computational efficiency by combining time-step and mesh adaptation strategies. This constitutes a natural extension of our methodology. 2. IMPLEMENT contact algorithms for rigid-body dynamics that will preserve our high-order temporal accuracy method. We favor using Lagrange multipliers for inequalities since they are free from approximations introduced by penalty methods for instance. 3. APPLY the formulation to problems with very low mass ratios that are relevant to offshore applications. Validation through experimental collaborative work between the low Reynolds number chanel of the Laboratoire de Mécanique des Fluides and Fluid-Structure Interaction Laboratory of the École Polytechnique de Montréal. We have identified the following problems of practical relevance: a. Riser tower torsional and translational galloping, b. Behavior of buoyancy can, c. Riser assemblies converging to an offshore platform, This generic research is innovative, as it will lead to the development and validation of computational models to shed insight into flow-­induced vibration problems typical to offshore mechanics. The focus on low mass ratio constitutes a real added value since it is an identified weakness of present CFD/CSD softwares. Our work is motivated by the need to develop the tools required by the industry to operate safely future oil offshore field developments in Canadian ultra-deep waters. Our approach offers excellent perspectives of success because it is a natural extension of existing engineering design procedures.

流固耦合 (FSI) 对于许多工程系统的设计至关重要。从适航性到飞机机动性，几乎所有机械系统都涉及结构和流体流动之间一定程度的耦合。在蒙特利尔理工学院，我们为通用 FSI 开发了有效的整体全耦合算法，并具有适用于 3D 非稳态配置的灵活结构。我们的工作引起了足够的兴趣，以至于多家公司资助了我们研究的扩展（Gaz Transport & Technigaz、Commissariat à l’Énergie Atomique、TOTAL SA）。 我们提出的研究是我们之前对 FSI 模拟研究的自然延伸。它将重点关注基本公式和计算问题（接触、谱元方法），以便对因不可压缩流体流动引起的大位移和变形的结构进行精确和一致的有限元模拟。 我们的目标是扩展 FSI 配方，以应对海上工业中突出而典型的挑战：质量比极低（零）的海上结构的流动引起的振动，与立管的流动布置和立管塔的舞动一致。通常的解耦算法在这些问题上惨败。此外，当前在更深水域钻探的趋势意味着将石油从海底输送到海面的立管管线现在跨度超过 2000 米，这需要设计新的浮力装置和新的立管概念。立管、浮标和立管塔的动态行为是由强烈的流激振动引起的，而传统的松散耦合算法很难处理这种振动。我们相信，我们的完全耦合方法可以克服这些新的极端 FSI 带来的许多困难。 为了实现我们的目标，我们确定了以下目标： 1. 完善我们的全耦合整体计算方法，以提高其准确性和计算效率。我们将把有限元公式扩展到等参、高阶谱元素，以提高空间精度，并通过结合时间步长和网格自适应策略从更高的计算效率中受益。这是我们方法论的自然延伸。 2. 实现刚体动力学的接触算法，这将保留我们的高阶时间精度方法。我们赞成使用拉格朗日乘子来解决不等式，因为它们不受例如惩罚方法引入的近似的影响。 3. 将公式应用于与海上应用相关的质量比非常低的问题。通过流体力学实验室的低雷诺数通道和蒙特利尔理工学院流固耦合实验室之间的实验合作进行验证。我们发现了以下具有实际意义的问题： 一个。立管塔扭转和平移驰骋， b.浮力行为可以， c.立管组件汇聚到海上平台， 这项通用研究具有创新性，因为它将促进计算模型的开发和验证，以深入了解海上力学典型的流引起的振动问题。对低质量比的关注构成了真正的附加值，因为它是当前 CFD/CSD 软件的一个明显弱点。我们的工作动机是需要开发行业所需的工具，以便安全地运营未来加拿大超深水域的海上油田开发。我们的方法提供了出色的成功前景，因为它是现有工程设计程序的自然延伸。